This invention relates to a machine for forming cylindrical bales of crop.
Machines, towed by a tractor, for forming large cylindrical bales of hay (so-called "round balers") are well known. As the machine advances, the crop is removed from a windrow by a pick-up mechanism and delivered rearwardly to a baling chamber where it is rolled round upon itself into a bale.
In one form of such a machine the baling chamber is defined by runs of side-by-side belts which move outwardly to enlarge the chamber so as to accomodate the bale as it grows in size. The belts are trained over rolls connected to a drive. A pair of rolls is sited at the top of chamber and these rolls are carried by a swingable tension arm on either side of the machine enabling the two rolls to swing upwardly as the girth of the bale increases. Foreign bodies, particularly stones, can find their way between the belts and their associated rolls and then become trapped causing the belts to deviate from their required path over the rolls. As the baling chamber grows in size with the bale being formed, the angle of the belts trained over a roll will change, and this makes the problem more difficult to solve. One roll particularly exposed to stones which can cause poor belt tracking is that located at the lower forward part of the baling chamber, i.e. the lower front belt driving roll which is vulnerable both to stones falling onto it after passing through gaps between neighboring belts and to stones thrown up by a crop pick-up which is disposed immediately under it in the type of machine which is fed from the underside.
The invention reduces the tendency of stones and other foreign bodies to be trapped between belts and an associated roll in a round baler.